The present invention relates generally to medical devices, and more particularly to an intubation instrument that utilizes a protective sheath disposed about a tube for preventing infection as the tube passes through a body passage.
Intubation devices are often inserted through a bacterially contaminated body passage before terminating in a naturally sterile milieu. Such intubation devices inherently transfer pathogens, such as bacteria, from the contaminated passage into the sterile milieu during the insertion process, thereby increasing susceptibility to infection.
One example of a well known intubation instrument is a bladder catheter, which is a long tubular device that is inserted into the urethra and passed into the bladder to effect the evacuation of urine from the bladder. Urinary tract infections are often induced upon insertion of a conventional bladder catheter, by the transport of bacteria-laden urethral mucus from the distal urethra and external genitalia into the bladder.
Reducing the occurrence of infection caused by intubation devices, for example, bladder catheters, has heretofore been difficult and ineffective. One known arrangement described in U.S. Pat. No. 3,421,509, provides for the insertion of a short protective sleeve into an outer extremity of the urethra before the bladder catheter itself is inserted. Subsequently, the catheter is inserted through the urethra and sleeve, thereby attempting to avoid contact with the contaminated area of the urethra. However, because the urethra is a collapsible tubular membrane, utilization of such a protective sleeve is ineffective because placement of the sleeve in the urethra carries bacterially contaminated mucus further into the urethra. Thus, the use of a protective sleeve is ineffective because even though the catheter initially passes through the sleeve the catheter eventually contacts an accumulation of bacterially contaminated mucus on the internally disposed end of the sleeve. In addition, the protective sleeve merely attempts to avoid contact with, while not removing, any of the harmful contaminated mucus and therefore a significant risk of infection is still present.
U.S. Pat. No, 3,084,693, discloses a catheter that utilizes a membrane having a ring shaped "peripheral stop" at one end. It is also exemplary of an ineffective prior attempt to reduce the onset of infection caused by intubation devices. The "peripheral stop" is retained by the external genitalia thereby causing the membrane to unroll during subsequent insertion of the catheter, in an attempt to create a sterile surface as the catheter advances internally thereof. Unfortunately, the membrane is positioned in a static manner relative to the urethra and disadvantageously remains static therein as the catheter advances. The static nature of the membrane having a "peripheral stop" is undesirable because the bacterially contaminated mucus remains in the urethra and hence a significant risk of infection is still present because the mucus is not transported away from the urethra.